This application refers to a coupling device with hinged retaining catches which is especially useful for coupling together tubes made of any material, including metal.
Many tube-coupling or connecting devices are known which consist basically of two or more concentric elements that can be screwed together, the tightening up of which leads to the retention of the end of the tubular body that is to be joined on. However, these devices, besides not generally offering enough of a guarantee as regards the holding of the smooth end of the joined tube, show certain deficiencies concerning the making of such a connection.
The device which is the object of this application differs from those previously known both in the simplicity of its design and the ease and efficiency with which the connection can be made, the hold being assured by means of swivel catches hinged peripherally to the front of the inner body, these catches having a tendency to open but which will close up gradually when being screwed on, with the possibility of these catches being fitted with an additional, non-slip hardfacing to ensure retention of the end of the tube that has to be connected, even when the latter is made of very rigid material, including metal.
In accordance with the above, an inherent characteristic of the new idea proposed is that, with the coupling device being msde up of two basic concentric parts which can be screwed together, besides the usual O-ring seal, the part constituting the inner body presents, from the front, a varying number of peripheral hinged catches which will depend on said inner body, these having been obtained preferably by means of moulding of thermoplastic materials, the peripheral catches being joined in relation to the inner body of the connection, by means of the respective hinge formed by a thinning down of the actual material, with the possibility of swivelling open or closed opposite the opening to the inner body of the connection, but with a permanent tendency to open in order to facilitate entry of the end of the tube to be connected.
These catches, with a tendency to open, will be housed inside the outer body of the connection such that the screwing on of this outer body will cause them to close up gradually, in the same way as the unscrewing of said body will allow the catches to open slightly thanks to their constant tendency to swivel apart from each other, an opening effect towards which the elastic O-ring behind the catches will be able to collaborate.
Another characteristic worth emphasising and which is related to the above concerns the screwing together of the two basic concentric parts, which will initially require overcoming a ring-shaped retaining ridge fitted on the inner body and shaped to facilitate this initial operation but which will later serve as a stop for marking the appropriate limits for screwing and unscrewing so that, by unscrewing until the stop comes into play, without separating the two parts of the device, it will be easy to introduce the end of the tube to be connected, which will be received by the fixing catches in a suitably open position, while by screwing up until the opposite stop acts equally, the catches will gain a secure hold on the end of the connected tube.
In order to guarantee this hold, the hinged retaining catches, usually of moulded thermoplastic material, may be fitted with a non-slip hardfacing made up of super-imposed metal parts adjusted to the toothing of the catch, said parts having sharp retaining edges which will act on the connected tube preventing it from slipping all the time the device is kept screwed together.